1. Field of Invention
The present invention relates to a liquid-crystal display panel having liquid crystal encapsulated between a pair of transparent substrates, the transparent substrates having a plurality of electrodes formed thereon, and a method for inspecting the substrate electrodes for short-circuiting.
2. Description of Related Art
Generally, a liquid crystal panel is produced by bonding a pair of transparent substrates with a sealing agent so that a gap is formed, and encapsulating liquid crystal in the gap. A liquid-crystal display panel is produced when auxiliary units are included, such as an integrated circuit (IC) for driving the liquid crystal, a backlight and a casing.
In the liquid-crystal display panel, transparent electrodes for applying voltages to the liquid crystal are formed on the respective transparent substrates. The transparent electrodes are formed in a predetermined layout, taking the form of a stripe, or in a special pattern, for example, a numeral, a character, or a particular design. Since the transparent electrodes are formed in extremely fine dimensions, there is a possibility that they will touch each other to cause short-circuit defects. Accordingly, when producing a liquid-crystal display panel, it is necessary to perform a pre-production phase inspection to ascertain whether or not short-circuits are present among a plurality of transparent electrodes.
For such electrode inspection there is a conventional method in which two inspection probes, arranged at a predetermined interval, are brought into contact with each transparent electrode. Whether or not adjacent transparent electrodes are short-circuited is determined based on whether or not both inspection probes conduct. Ordinarily, the inspection is performed by putting the two inspection probes on two adjacent transparent electrodes, respectively. This type of inspection method is disclosed in, for example, Japanese Unexamined Patent Publication No. 61-194484 where an inspection method for finding short-circuiting is performed by bringing inspection probes in contact with inspection patterns arranged at regular intervals.
However, conventional inspection methods are premised in that all inspection patterns are arranged to correspond to a preset interval of the inspection probes, without consideration for a case in which the intervals of the inspection patterns change. Thus, when the intervals of the inspection patterns change, the interval of the inspection probes must be adjusted each time in accordance with the change. However, it is not preferable to adjust the interval of the inspection probes each time because these adjustments remarkably decreases the productivity of liquid-crystal display panels. While the inspection probes can be arranged in a special form in accordance with the inspection patterns on a transparent substrate to be inspected, application will be limited to a predetermined inspection pattern, and cannot be applied to other electrode patterns, resulting in remarkably low usability for general inspection purposes.
In addition, inspection methods with inspection probes includes a method in which a plurality of transparent electrodes to be inspected are scanned by two inspection probes arranged at a predetermined interval. This method can be executed without difficulty when all the inspection patterns are arranged at intervals (inspection intervals) corresponding to the predetermined interval of the inspection probes. However, if there are inspection patterns arranged at intervals different from the inspection intervals in a region (inspection region) which is scanned by the inspection probes, the two probes cannot be simultaneously brought in contact with the inspection patterns. Thus, the inspection patterns cannot be inspected.
In order to overcome the above problems, it is an object of the present invention to provide a liquid-crystal display panel and method for inspecting the same in which, even if the electrodes to be inspected are formed on a transparent substrate and include different-interval electrodes, all the electrodes can be inspected without difficulty by using multi-purpose inspection probes arranged at regular intervals.